This invention relates to compact low-pressure gas discharge lamps and more particularly to a system including a lamp assembly and a power supply for the lamp assembly. The invention is especially adapted to providing practical dimming capabilities for compact fluorescent lamps.
Compact fluorescent lamps have long been known for their high luminous efficiency and have made great strides in replacing relatively inefficient incandescent bulbs. Because fluorescent lamps are typically provided in elongated tubular form, efforts have been made to reconfigure their light transmitting enclosures into a series of short parallel tubes or stubs. Prior attempts have focused on reforming the light transmitting enclosure of a single gas discharge lamp into a serpentine configuration, such as illustrated in U.S. Pat. No. 4,347,460, or into a series of cross coupled tubes as illustrated in U.S. Pat. No. 4,545,774. Such prior attempts have resulted in lamps that could be manufactured only by extremely complex manufacturing processees.
There has been a long felt yet unmet need for practical dimming capabilities for compact fluorescent lamps. While various schemes have been proposed, none of them have been commercially acceptable. This is believed to be a result of the unusual and demanding operating characteristics of such compact fluorescent lamps. Dimming techniques that are suitable for incandescent lamps are incompatible with fluorescent lamp circuits.
Because the primary benefit of compact fluorescent lamps is envisioned to be in the replacement of incandescent lamps, compact fluorescent lamp adapters have been used for the purposes of adapting conventional incandescent lamp fixtures for use with compact fluorescent lamps. This not only avoids unnecessary expense in equipment replacement but allows the substitution to be easily performed by the end user. Such adapters have not been without their drawbacks. Compact fluorescent lamps are heat sensitive, and the waste heat produced by the lamp ballast circuit tends to reduce lamp longevity when combined in the same assembly with the fluorescent lamp.